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-ray during dehydrationIrisawa, Keita; Kudo, Isamu*; Taniguchi, Takumi; Namiki, Masahiro*; Osugi, Takeshi; Nakazawa, Osamu
QST-M-8; QST Takasaki Annual Report 2016, P. 63, 2018/03
A solidification technique with minimized water content is being developed using a phosphate cement for safe storage of secondary radioactive wastes in the Fukushima Daiichi Nuclear Power Plant. To understand the applicability of the solidification technique for the actual secondary wastes, phosphate cement during dehydration was irradiated by 
Co -ray. The G(H
) for the phosphate cement decreased with time during dehydration, and was not detected after 7 days. Moreover, the Co -ray irradiation during dehydration did not change the crystalline and amorphous phases of the phosphate cement.
rster effectOgawa, Tatsuhiko; Yamaki, Tetsuya*; Sato, Tatsuhiko
QST-M-8; QST Takasaki Annual Report 2016, P. 34, 2018/03
Scintillators are used for detection of various radiation such as electrons, -rays, protons and heavy ions. Fundamentally, scintillators emit lights depending on the deposition energy, but light yield is suppressed (i.e., quenching) in case of highly ionizing radiation. In this study, light yield of scintillators was calculated based on following assumptions; scintillation is attributed to excitation of phosphor molecules by incident particles, Frster effect by the damaged phosphor molecules is the mechanism responsible for quenching, and excitation and damage of phosphor molecules can be calculated by molecular-scale radiation transport simulation code RITRACKS. Protons from 0.1 MeV to 150 MeV and electrons from 0.1 MeV to 1 MeV were directed to full-stop thick NE102 scintillator as incident particles and the light yield of scintillators was calculated. Both calculated light yields and earlier measurement data showed that the light yield by electrons is proportional to incident energy whereas the light yield by protons increases with increase in incident energy in a non-linearly. Thus the simulation in this study can accurately reproduce the light yield of scintillators in radiation detection.
Motooka, Takafumi
QST-M-8; QST Takasaki Annual Report 2016, P. 73, 2018/03
Previous corrosion test of carbon steel in dilute artificial seawater under Co-60 -ray irradiation has indicated that corrosion rate was enhanced at absorbed dose rates: 
100 Gy/h and rust color was changed from black to dark brown. In the present study, the corrosion mechanism of carbon steel under Co-60 -ray irradiation was investigated by identification of rust. rays enhanced oxidation of iron ions from di-valent to tri-valent. Rust formed under irradiation had higher oxidation state.
Ito, Yoshiyuki; Matsushima, Ryotatsu; Sato, Fuminori
QST-M-8; QST Takasaki Annual Report 2016, P. 69, 2018/03
no abstracts in English
Sato, Junya; Kikuchi, Hiroshi*; Kato, Jun; Sakakibara, Tetsuro; Matsushima, Ryotatsu; Sato, Fuminori; Kojima, Junji; Nakazawa, Osamu
QST-M-8; QST Takasaki Annual Report 2016, P. 62, 2018/03
no abstracts in English
Abe, Tomohisa; Shimazaki, Takejiro; Osugi, Takeshi; Yamada, Naoto*; Yuri, Yosuke*; Sato, Takahiro*
QST-M-8; QST Takasaki Annual Report 2016, P. 61, 2018/03
no abstracts in English
Sakai, Takuro; Iikura, Hiroshi; Yamada, Naoto*; Sato, Takahiro*; Ishii, Yasuyuki*; Uchida, Masaya*
QST-M-8; QST Takasaki Annual Report 2016, P. 140, 2018/03
cluster ionsKitamura, Akane; Yamaki, Tetsuya*; Chiba, Atsuya*; Usui, Aya
QST-M-8; QST Takasaki Annual Report 2016, P. 37, 2018/03
We investigated the track-etched surface of PVDF films irradiated with C cluster ions, comparing the data with C monoatomic ions. PVDF films were irradiated with 6 MeV C cluster ions. The energy of the each carbon ion is 100 keV/atom; thus, for comparison, the PVDF films were also irradiated with 100 keV C ions. SEM and AFM observation showed that the surface irradiated with C cluster ions apparently possessed flat-bottomed pores with an average diameter and depth of approximately 400 and 250 nm, respectively. On the other hand, track-etched pores were also formed on the surface irradiated with C ions, but their morphology was irregular or obscure. In the irradiation with the C cluster ions, the surface diameter of track-etched pores increased with increasing the etching time. The tracks of the 100 keV C ions seemed to be hardly developed by the etching when the time. In conclusion, the C cluster ions irradiation caused a large size of etchable tracks on the PVDF surface. The result could represent the effect of local and simultaneous collision by the aggregated ions.
Yamaki, Tetsuya*; Goto, Mitsuaki*; Sawada, Shinichi*; Koshikawa, Hiroshi*; Kitamura, Akane; Higa, Mitsuru*
QST-M-8; QST Takasaki Annual Report 2016, P. 35, 2018/03
We prepared ion exchange membranes by a heavy-ion-track grafting method, and then used them for seawater concentration process. Both the water uptake and resistance were lower for our ion-track grafted membranes than for the conventional -ray-grafted membranes. The results would be because local and high-density energy deposition due to the ion beam enabled us to control the membrane structure in a nanometer scale. We demonstrate our membranes are suitable for this application.
